4. Permanent tissues
1. Epidermal tissue
• Outermost layer – covers the stems, leaves
and roots of young plants.
• Flat and has large vacuole
• Wall - covered with cuticle
• Root – has root hairs
• Chloroplast – guard cells
6. Permanent tissue
2. Ground tissue
• parenchyma – thin primary walls and large
vacuole ; store sugar and starch ; gives support
and shape to herbaceous plants.(leaf)
• collenchyma – unevenly thickened cell walls;
supports non-woody plants, young stems and
petioles.(stem)
• sclerenchyma – cell walls uniformly thickened
by lignin and may be dead; give support and
mechanical strength.(root)
13. Regulating the internal
environment
Definition
Why
need to maintain an optimal
internal environment?
Factors that affect the internal
environment?
Homeostasis??
- system that regulates its internal
environment so as to maintain a
stable, constant condition
